upd: sync local changes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/Base/Lists/TransitionWidget.cs

@@ -0,0 +1,128 @@
+using Cthangover.Core.Mods;
+using Cthangover.Core.Mods.Resolvers;
+using Cthangover.Core.UI.Theming;
+using Godot;
+
+namespace Cthangover.Mods.Interface.Base.Lists
+{
+    /// <summary>
+    /// Shader-based scene transition: animates a "progress" uniform on the
+    /// background's ShaderMaterial via a Godot Tween, then reveals content after
+    /// a configurable delay. The shader is resolved through the mod system
+    /// (ModManager.ResolveShader), allowing mods to replace the transition effect.
+    /// Uses an easeInOut curve for the progress ramp. Material is duplicated on
+    /// first use so each instance gets its own shader parameters. On tree exit,
+    /// the duplicated material is disposed to avoid leaks.
+    /// </summary>
+    public abstract partial class TransitionWidget : Widget
+    {
+        private static readonly StringName ProgressParam = "progress";
+
+        [Export] private TextureRect imgBackground;
+        [Export] private Control contentGroup;
+        [Export] private float transitionDuration = 0.8f;
+        [Export] private float contentDelay = 0.05f;
+
+        private ShaderMaterial materialInstance;
+        private Tween transitionTween;
+
+        /// <summary>
+        /// Shows the widget base, then creates or reuses a shader material for the background and starts the transition tween.
+        /// Material is duplicated from <c>imgBackground.Material</c> on first call so each instance gets independent shader parameters.
+        /// </summary>
+        public override void Show()
+        {
+            base.Show();
+
+            if (materialInstance == null && imgBackground != null)
+            {
+                materialInstance = imgBackground.Material?.Duplicate() as ShaderMaterial;
+                if (materialInstance == null)
+                {
+                    materialInstance = new ShaderMaterial();
+                    var shader = Shaders.Resolve("scene_transition");
+                    if (shader != null)
+                        materialInstance.Shader = shader;
+                }
+                imgBackground.Material = materialInstance;
+                materialInstance.SetShaderParameter(ProgressParam, 0f);
+            }
+
+            if (transitionTween != null)
+            {
+                transitionTween.Kill();
+                transitionTween = null;
+            }
+
+            RunShowAnimation();
+        }
+
+        /// <summary>Kills the active transition tween if one is running, then calls base <see cref="Widget.Hide"/>.</summary>
+        public override void Hide()
+        {
+            if (transitionTween != null)
+            {
+                transitionTween.Kill();
+                transitionTween = null;
+            }
+            base.Hide();
+        }
+
+        private void RunShowAnimation()
+        {
+            if (contentGroup != null)
+            {
+                contentGroup.Modulate = UiTokens.Alpha(UiTokens.White, 0f);
+                contentGroup.MouseFilter = MouseFilterEnum.Ignore;
+            }
+
+            transitionTween = CreateTween();
+            transitionTween.SetProcessMode(Tween.TweenProcessMode.Physics);
+            transitionTween.TweenMethod(Callable.From<float>(OnProgressUpdate), 0f, 1f, transitionDuration);
+            transitionTween.Finished += OnTweenFinished;
+        }
+
+        private void OnProgressUpdate(float t)
+        {
+            float curvedT = EaseInOut(t);
+            if (imgBackground?.Material is ShaderMaterial mat)
+                mat.SetShaderParameter(ProgressParam, curvedT);
+        }
+
+        private void OnTweenFinished()
+        {
+            if (imgBackground?.Material is ShaderMaterial mat)
+                mat.SetShaderParameter(ProgressParam, 1f);
+
+            var timer = GetTree().CreateTimer(contentDelay);
+            timer.Timeout += () =>
+            {
+                if (contentGroup != null)
+                {
+                    contentGroup.Modulate = UiTokens.White;
+                    contentGroup.MouseFilter = MouseFilterEnum.Stop;
+                }
+            };
+
+            transitionTween = null;
+        }
+
+        private static float EaseInOut(float t)
+        {
+            return t < 0.5f ? 2f * t * t : 1f - Mathf.Pow(-2f * t + 2f, 2f) / 2f;
+        }
+
+        /// <summary>Disposes the per-instance shader material created for the transition.</summary>
+        public override void _ExitTree()
+        {
+            if (materialInstance != null)
+            {
+                materialInstance.Dispose();
+                materialInstance = null;
+            }
+            base._ExitTree();
+        }
+    }
+}
+
+